Welcome! In this lesson, we'll explore two fundamental software design patterns: the Facade and Adapter patterns. Our goal is to understand how these patterns help maintain backward compatibility while introducing new features in PHP. Backward compatibility ensures that updates do not disrupt existing systems, allowing new functionalities to be incorporated without altering the current codebase. Think of the Facade and Adapter patterns as universal remotes, bridging new technology with old devices in PHP applications.

Design patterns are established solutions to common problems in software design and represent the accumulated wisdom of experienced developers. Among the various design patterns, today we'll focus on the Facade and Adapter patterns. The Facade pattern offers a simplified interface to a complex subsystem, while the Adapter pattern allows for classes with incompatible interfaces to collaborate. Let's delve deeper into their use cases using PHP.

The Facade pattern reduces complexity by providing a higher-level interface. For example, consider an online shopping application. When a user places an order, it triggers multiple operations. Using the Facade pattern, we can build an OrderFacade class to streamline these operations: